During recent years, gasification technology has gained a high potential and attractiveness to convert biomass and other solid wastes into a valuable syngas for energy production or synthesis of new biofuels. The implementation of real gasification facilities implies a good insight of all expenses that are involved, namely investments required in equipment during the project and construction phases (capital expenditures, CapEx) and costs linked to the operation of the plant, or periodic maintenance interventions (operational expenditures, OpEx) or costs related to operations required for an efficient and sustainable performance of a gasification plant (e.g., feedstock pre-treatment and management of by-products). Knowledge of these economic parameters and their corresponding trends over time may help decision-makers to make adequate choices regarding the eligible technologies and to perform comparisons with other conventional scenarios. The present work aims to provide an overview on CapEx associated with gasification technologies devoted to convert biomass or solid waste sources, with a view of reducing the carbon footprint during energy generation or production of new energy carriers. In addition, an analysis of technology cost trends over time using regression methods is also presented, as well as an evaluation of specific capital investments according to the amount of output products generated for different gasification facilities. The novelty of this work is focused on an analysis of CapEx of existing gasification technologies to obtain distinct products (energy and fuels), and to determine mathematical correlations relating technology costs with time and product output. For these purposes, a survey of data and categorization of gasification plants based on the final products was made, and mathematical regression methods were used to obtain the correlations, with a statistical analysis (coefficient of determination) for validation. Specific investments on liquid biofuel production plants exhibited the highest decreasing trend over time, while electricity production became the least attractive solution. Linear correlations of specific investment versus time fitted better for electricity production plants (R² = 0.67), while those relating the product output were better for liquid biofuel plants through exponential regressions (R² = 0.65).

Biochar produced during the thermochemical decomposition of biomass is an environmentally friendly replacement for different carbon materials and can be used for carbon sequestration to mitigate climate change. In this paper, current biochar production processes and top market applications are reviewed, as well as emerging biochar uses gaining momentum in the market. Various application fields of biochar, including agricultural applications (e.g., soil conditioning), adsorption (for soil and water pollutants), carbon sequestration, catalysis, or incorporation into composites or construction materials, are also presented and discussed. According to this literature overview, slow pyrolysis is the preferred process for biochar production, whereas agricultural applications (for soil conditioning and fertilization) are the most studied and market-ready solutions for biochar use. The Alentejo region (Portugal) shows tremendous potential to be a major player in the developing biochar market considering feedstock availability and large areas for biochar agricultural application. Biochar’s production potential and possible benefits were also estimated for this Portuguese region, proving that agricultural application can effectively lead to many environmental, economic, and social gains.

Hydrogen is undeniably one of the most promising options for producing energy with minimal environmental impact. However, current hydrogen production is still derived from carbon-intensive processes relying on fossil fuels. Biomass is a sustainable and versatile resource that can be converted into hydrogen through biological and thermochemical pathways from a large variety of feedstocks and technologies. This work reviews and compares existing biomass-to-hydrogen technologies, focusing on their characteristics, maturity level, benefits, limitations, and techno-economic and lifecycle environmental impacts. Less-developed biological conversion methods are characterized by low efficiencies and hydrogen productivity. More mature thermochemical routes enable higher efficiencies and hydrogen yields. Overall, while thermochemical processes suit centralized large-scale hydrogen production, biological pathways offer decentralized options, necessitating continued innovation for integration into future energy strategies. Some of these technologies, such as anaerobic digestion (best-case: 1.28 EUR/kgH₂) and conventional gasification (best-case: 1.79 EUR/kgH₂), emerge as promising, sustainable, and affordable alternatives for renewable hydrogen generation, offering production costs comparable to those of natural gas steam reforming (0.92–2.8 EUR/kgH₂).